<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
</html>
<script>
    var score=Number(prompt("请输入成绩"))
    if(score>=90){
        alert("优秀")
    }else if(score>=80&&score<90){
        alert('良好')
    }else if(score>=60&&score<80){
        alert("合格")
    }else{
        alert("不合格")
    }
</script>